[Textfield] Consider select all status for select all context menu

ui/views/controls/textfield/textfield.cc

Index: ui/views/controls/textfield/textfield.cc
diff --git a/ui/views/controls/textfield/textfield.cc b/ui/views/controls/textfield/textfield.cc
index 1586362197bbeeefe7910675eb0c4747e5441b76..81d8e6a1dbbcd1287559fa48ed7391259deec263 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -1546,7 +1546,7 @@ bool Textfield::IsTextEditCommandEnabled(ui::TextEditCommand command) const {
           ui::CLIPBOARD_TYPE_COPY_PASTE, &result);
       return editable && !result.empty();
     case ui::TextEditCommand::SELECT_ALL:
-      return !text().empty();
+      return !text().empty() && GetSelectedRange().length() != text().length();
     case ui::TextEditCommand::TRANSPOSE:
       return editable && !model_->HasSelection() &&
              !model_->HasCompositionText();